From c7d7d620dcbd2a1c595092280ca943f2fced7bbd Mon Sep 17 00:00:00 2001
From: Pan Bian <bianpan2016@163.com>
Date: Fri, 30 Nov 2018 14:09:18 -0800
Subject: [PATCH] hfsplus: do not free node before using
Git-commit: c7d7d620dcbd2a1c595092280ca943f2fced7bbd
Patch-mainline: v4.20-rc5
References: bsc#1051510
hfs_bmap_free() frees node via hfs_bnode_put(node). However it then
reads node->this when dumping error message on an error path, which may
result in a use-after-free bug. This patch frees node only when it is
never used.
Link: http://lkml.kernel.org/r/1543053441-66942-1-git-send-email-bianpan2016@163.com
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
fs/hfsplus/btree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index 236efe51eca6..66774f4cb4fd 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -466,14 +466,15 @@ void hfs_bmap_free(struct hfs_bnode *node)
nidx -= len * 8;
i = node->next;
- hfs_bnode_put(node);
if (!i) {
/* panic */;
pr_crit("unable to free bnode %u. "
"bmap not found!\n",
node->this);
+ hfs_bnode_put(node);
return;
}
+ hfs_bnode_put(node);
node = hfs_bnode_find(tree, i);
if (IS_ERR(node))
return;
--
2.16.4